diff --git a/doc/developer-notes.md b/doc/developer-notes.md index ae73c9767..1cc111956 100644 --- a/doc/developer-notes.md +++ b/doc/developer-notes.md @@ -1,530 +1,530 @@ Developer Notes =============== Various coding styles have been used during the history of the codebase, and the result is not very consistent. However, we're now trying to converge to a single style, so please use it in new code. Old code will be converted gradually and you are encouraged to use the provided [clang-format-diff script](/contrib/devtools/README.md#clang-format-diffpy) to clean up the patch automatically before submitting a pull request. - Basic rules specified in [src/.clang-format](/src/.clang-format). - Braces on new lines for namespaces, classes, functions, methods. - Braces on the same line for everything else. - 4 space indentation (no tabs) for every block except namespaces. - No indentation for `public`/`protected`/`private` or for `namespace`. - No extra spaces inside parenthesis; don't do ( this ) - No space after function names; one space after `if`, `for` and `while`. - Always add braces for block statements (e.g. `if`, `for`, `while`). - `++i` is preferred over `i++`. - Use CamelCase for functions/methods, and lowerCamelCase for variables. - GLOBAL_CONSTANTS should use UPPER_SNAKE_CASE. - namespaces should use lower_snake_case. - Function names should generally start with an English command-form verb (e.g. `ValidateTransaction`, `AddTransactionToMempool`, `ConnectBlock`) - Variable names should generally be nouns or past/future tense verbs. (e.g. `canDoThing`, `signatureOperations`, `didThing`) - Avoid using globals, remove existing globals whenever possible. - Class member variable names should be prepended with `m_` - DO choose easily readable identifier names. - DO favor readability over brevity. - DO NOT use Hungarian notation. - DO NOT use abbreviations or contractions within identifiers. - WRONG: mempool - RIGHT: MemoryPool - WRONG: ChangeDir - RIGHT: ChangeDirectory - DO NOT use obscure acronyms, DO uppercase any acronyms. - FINALLY, do not migrate existing code unless refactoring. It makes forwarding-porting from Bitcoin Core more difficult. The naming convention roughly mirrors [Microsoft Naming Conventions](https://docs.microsoft.com/en-us/dotnet/standard/design-guidelines/general-naming-conventions) C++ Coding Standards should strive to follow the [LLVM Coding Standards](https://llvm.org/docs/CodingStandards.html) Code style example: ```c++ // namespaces should be lower_snake_case namespace foo_bar_bob { /** * Class is used for doing classy things. All classes should * have a doxygen comment describing their PURPOSE. That is to say, * why they exist. Functional details can be determined from the code. * @see PerformTask() */ class Class { private: //! memberVariable's name should be lowerCamelCase, and be a noun. int m_memberVariable; public: /** * The documentation before a function or class method should follow Doxygen * spec. The name of the function should start with an english verb which * indicates the intended purpose of this code. * * The function name should be should be CamelCase. * * @param[in] s A description * @param[in] n Another argument description * @pre Precondition for function... */ bool PerformTask(const std::string& s, int n) { // Use lowerChamelCase for local variables. bool didMore = false; // Comment summarizing the intended purpose of this section of code for (int i = 0; i < n; ++i) { if (!DidSomethingFail()) { return false; } ... if (IsSomethingElse()) { DoMore(); didMore = true; } else { DoLess(); } } return didMore; } } } ``` Doxygen comments ----------------- To facilitate the generation of documentation, use doxygen-compatible comment blocks for functions, methods and fields. For example, to describe a function use: ```c++ /** * ... text ... * @param[in] arg1 A description * @param[in] arg2 Another argument description * @pre Precondition for function... */ bool function(int arg1, const char *arg2) ``` A complete list of `@xxx` commands can be found at http://www.stack.nl/~dimitri/doxygen/manual/commands.html. As Doxygen recognizes the comments by the delimiters (`/**` and `*/` in this case), you don't *need* to provide any commands for a comment to be valid; just a description text is fine. To describe a class use the same construct above the class definition: ```c++ /** * Alerts are for notifying old versions if they become too obsolete and * need to upgrade. The message is displayed in the status bar. * @see GetWarnings() */ class CAlert { ``` To describe a member or variable use: ```c++ int var; //!< Detailed description after the member ``` or ```cpp //! Description before the member int var; ``` Also OK: ```c++ /// /// ... text ... /// bool function2(int arg1, const char *arg2) ``` Not OK (used plenty in the current source, but not picked up): ```c++ // // ... text ... // ``` A full list of comment syntaxes picked up by doxygen can be found at http://www.stack.nl/~dimitri/doxygen/manual/docblocks.html, but if possible use one of the above styles. To build doxygen locally to test changes to the Doxyfile or visualize your comments before landing changes: ``` # at the project root, call: doxygen doc/Doxyfile # output goes to doc/doxygen/html/ ``` Development tips and tricks --------------------------- **compiling for debugging** Run configure with the --enable-debug option, then make. Or run configure with CXXFLAGS="-g -ggdb -O0" or whatever debug flags you need. **debug.log** If the code is behaving strangely, take a look in the debug.log file in the data directory; error and debugging messages are written there. The -debug=... command-line option controls debugging; running with just -debug or -debug=1 will turn on all categories (and give you a very large debug.log file). The Qt code routes qDebug() output to debug.log under category "qt": run with -debug=qt to see it. **writing tests** For details on unit tests, see `unit-tests.md` -For details on functional tests, see `/test/README.md` +For details on functional tests, see `functional-tests.md` **writing script integration tests** Script integration tests are built using `src/test/script_tests.cpp`: 1. Uncomment the line with `#define UPDATE_JSON_TESTS` 2. Add a new TestBuilder to the `script_build` test to cover your test case. 3. `make && ./src/test/test_bitcoin --run_test=script_tests` 4. Copy your newly generated test JSON from `/src/script_tests.json.gen` to `src/test/data/script_tests.json`. Please commit your TestBuilder along with your generated test JSON and cleanup the uncommented #define before code review. **testnet and regtest modes** Run with the -testnet option to run with "play bitcoins" on the test network, if you are testing multi-machine code that needs to operate across the internet. If you are testing something that can run on one machine, run with the -regtest option. In regression test mode, blocks can be created on-demand; see test/functional/ for tests that run in -regtest mode. **DEBUG_LOCKORDER** Bitcoin Core is a multithreaded application, and deadlocks or other multithreading bugs can be very difficult to track down. Compiling with -DDEBUG_LOCKORDER (configure CXXFLAGS="-DDEBUG_LOCKORDER -g") inserts run-time checks to keep track of which locks are held, and adds warnings to the debug.log file if inconsistencies are detected. Locking/mutex usage notes ------------------------- The code is multi-threaded, and uses mutexes and the LOCK/TRY_LOCK macros to protect data structures. Deadlocks due to inconsistent lock ordering (thread 1 locks cs_main and then cs_wallet, while thread 2 locks them in the opposite order: result, deadlock as each waits for the other to release its lock) are a problem. Compile with -DDEBUG_LOCKORDER to get lock order inconsistencies reported in the debug.log file. Re-architecting the core code so there are better-defined interfaces between the various components is a goal, with any necessary locking done by the components (e.g. see the self-contained CKeyStore class and its cs_KeyStore lock for example). Threads ------- - ThreadScriptCheck : Verifies block scripts. - ThreadImport : Loads blocks from blk*.dat files or bootstrap.dat. - StartNode : Starts other threads. - ThreadDNSAddressSeed : Loads addresses of peers from the DNS. - ThreadMapPort : Universal plug-and-play startup/shutdown - ThreadSocketHandler : Sends/Receives data from peers on port 8333. - ThreadOpenAddedConnections : Opens network connections to added nodes. - ThreadOpenConnections : Initiates new connections to peers. - ThreadMessageHandler : Higher-level message handling (sending and receiving). - DumpAddresses : Dumps IP addresses of nodes to peers.dat. - ThreadFlushWalletDB : Close the wallet.dat file if it hasn't been used in 500ms. - ThreadRPCServer : Remote procedure call handler, listens on port 8332 for connections and services them. - BitcoinMiner : Generates bitcoins (if wallet is enabled). - Shutdown : Does an orderly shutdown of everything. Ignoring IDE/editor files -------------------------- In closed-source environments in which everyone uses the same IDE it is common to add temporary files it produces to the project-wide `.gitignore` file. However, in open source software such as Bitcoin Core, where everyone uses their own editors/IDE/tools, it is less common. Only you know what files your editor produces and this may change from version to version. The canonical way to do this is thus to create your local gitignore. Add this to `~/.gitconfig`: ``` [core] excludesfile = /home/.../.gitignore_global ``` (alternatively, type the command `git config --global core.excludesfile ~/.gitignore_global` on a terminal) Then put your favourite tool's temporary filenames in that file, e.g. ``` # NetBeans nbproject/ ``` Another option is to create a per-repository excludes file `.git/info/exclude`. These are not committed but apply only to one repository. If a set of tools is used by the build system or scripts the repository (for example, lcov) it is perfectly acceptable to add its files to `.gitignore` and commit them. Development guidelines ============================ A few non-style-related recommendations for developers, as well as points to pay attention to for reviewers of Bitcoin Core code. Wallet ------- - Make sure that no crashes happen with run-time option `-disablewallet`. - *Rationale*: In RPC code that conditionally uses the wallet (such as `validateaddress`) it is easy to forget that global pointer `pwalletMain` can be NULL. See `test/functional/disablewallet.py` for functional tests exercising the API with `-disablewallet` - Include `db_cxx.h` (BerkeleyDB header) only when `ENABLE_WALLET` is set - *Rationale*: Otherwise compilation of the disable-wallet build will fail in environments without BerkeleyDB General C++ ------------- - Assertions should not have side-effects - *Rationale*: Even though the source code is set to to refuse to compile with assertions disabled, having side-effects in assertions is unexpected and makes the code harder to understand - If you use the `.h`, you must link the `.cpp` - *Rationale*: Include files define the interface for the code in implementation files. Including one but not linking the other is confusing. Please avoid that. Moving functions from the `.h` to the `.cpp` should not result in build errors - Use the RAII (Resource Acquisition Is Initialization) paradigm where possible. For example by using `unique_ptr` for allocations in a function. - *Rationale*: This avoids memory and resource leaks, and ensures exception safety C++ data structures -------------------- - Never use the `std::map []` syntax when reading from a map, but instead use `.find()` - *Rationale*: `[]` does an insert (of the default element) if the item doesn't exist in the map yet. This has resulted in memory leaks in the past, as well as race conditions (expecting read-read behavior). Using `[]` is fine for *writing* to a map - Do not compare an iterator from one data structure with an iterator of another data structure (even if of the same type) - *Rationale*: Behavior is undefined. In C++ parlor this means "may reformat the universe", in practice this has resulted in at least one hard-to-debug crash bug - Watch out for out-of-bounds vector access. `&vch[vch.size()]` is illegal, including `&vch[0]` for an empty vector. Use `vch.data()` and `vch.data() + vch.size()` instead. - Vector bounds checking is only enabled in debug mode. Do not rely on it - Make sure that constructors initialize all fields. If this is skipped for a good reason (i.e., optimization on the critical path), add an explicit comment about this - *Rationale*: Ensure determinism by avoiding accidental use of uninitialized values. Also, static analyzers balk about this. - Use explicitly signed or unsigned `char`s, or even better `uint8_t` and `int8_t`. Do not use bare `char` unless it is to pass to a third-party API. This type can be signed or unsigned depending on the architecture, which can lead to interoperability problems or dangerous conditions such as out-of-bounds array accesses - Prefer explicit constructions over implicit ones that rely on 'magical' C++ behavior - *Rationale*: Easier to understand what is happening, thus easier to spot mistakes, even for those that are not language lawyers Strings and formatting ------------------------ - Use `std::string`, avoid C string manipulation functions - *Rationale*: C++ string handling is marginally safer, less scope for buffer overflows and surprises with `\0` characters. Also some C string manipulations tend to act differently depending on platform, or even the user locale - Use `ParseInt32`, `ParseInt64`, `ParseUInt32`, `ParseUInt64`, `ParseDouble` from `utilstrencodings.h` for number parsing - *Rationale*: These functions do overflow checking, and avoid pesky locale issues Variable names -------------- The shadowing warning (`-Wshadow`) is enabled by default. It prevents issues rising from using a different variable with the same name. Please name variables so that their names do not shadow variables defined in the source code. Threads and synchronization ---------------------------- - Build and run tests with `-DDEBUG_LOCKORDER` to verify that no potential deadlocks are introduced. As of 0.12, this is defined by default when configuring with `--enable-debug` - When using `LOCK`/`TRY_LOCK` be aware that the lock exists in the context of the current scope, so surround the statement and the code that needs the lock with braces OK: ```c++ { TRY_LOCK(cs_vNodes, lockNodes); ... } ``` Wrong: ```c++ TRY_LOCK(cs_vNodes, lockNodes); { ... } ``` Source code organization -------------------------- - Implementation code should go into the `.cpp` file and not the `.h`, unless necessary due to template usage or when performance due to inlining is critical - *Rationale*: Shorter and simpler header files are easier to read, and reduce compile time - Don't import anything into the global namespace (`using namespace ...`). Use fully specified types such as `std::string`. - *Rationale*: Avoids symbol conflicts GUI ----- - Do not display or manipulate dialogs in model code (classes `*Model`) - *Rationale*: Model classes pass through events and data from the core, they should not interact with the user. That's where View classes come in. The converse also holds: try to not directly access core data structures from Views. Subtrees ---------- Several parts of the repository are subtrees of software maintained elsewhere. Some of these are maintained by active developers of Bitcoin Core, in which case changes should probably go directly upstream without being PRed directly against the project. They will be merged back in the next subtree merge. Others are external projects without a tight relationship with our project. Changes to these should also be sent upstream but bugfixes may also be prudent to PR against Bitcoin Core so that they can be integrated quickly. Cosmetic changes should be purely taken upstream. There is a tool in contrib/devtools/git-subtree-check.sh to check a subtree directory for consistency with its upstream repository. Current subtrees include: - src/leveldb - Upstream at https://github.com/google/leveldb ; Maintained by Google, but open important PRs to Core to avoid delay - src/libsecp256k1 - Upstream at https://github.com/bitcoin-core/secp256k1/ ; actively maintaned by Core contributors. - src/crypto/ctaes - Upstream at https://github.com/bitcoin-core/ctaes ; actively maintained by Core contributors. - src/univalue - Upstream at https://github.com/jgarzik/univalue ; report important PRs to Core to avoid delay. Git and GitHub tips --------------------- - Github is not typically the source of truth for pull requests. See CONTRIBUTING.md for instructions on setting up your repo correctly. - Similarly, your git remote origin should be set to: `ssh://vcs@reviews.bitcoinabc.org:2221/source/bitcoin-abc.git` instead of github.com. See CONTRIBUTING.md for details. - For resolving merge/rebase conflicts, it can be useful to enable diff3 style using `git config merge.conflictstyle diff3`. Instead of <<< yours === theirs >>> you will see <<< yours ||| original === theirs >>> This may make it much clearer what caused the conflict. In this style, you can often just look at what changed between *original* and *theirs*, and mechanically apply that to *yours* (or the other way around). - When reviewing patches which change indentation in C++ files, use `git diff -w` and `git show -w`. This makes the diff algorithm ignore whitespace changes. This feature is also available on github.com, by adding `?w=1` at the end of any URL which shows a diff. - When reviewing patches that change symbol names in many places, use `git diff --word-diff`. This will instead of showing the patch as deleted/added *lines*, show deleted/added *words*. - When reviewing patches that move code around, try using `git diff --patience commit~:old/file.cpp commit:new/file/name.cpp`, and ignoring everything except the moved body of code which should show up as neither `+` or `-` lines. In case it was not a pure move, this may even work when combined with the `-w` or `--word-diff` options described above. - When looking at other's pull requests, it may make sense to add the following section to your `.git/config` file: [remote "upstream-pull"] fetch = +refs/pull/*:refs/remotes/upstream-pull/* url = git@github.com:bitcoin/bitcoin.git This will add an `upstream-pull` remote to your git repository, which can be fetched using `git fetch --all` or `git fetch upstream-pull`. Afterwards, you can use `upstream-pull/NUMBER/head` in arguments to `git show`, `git checkout` and anywhere a commit id would be acceptable to see the changes from pull request NUMBER. diff --git a/test/README.md b/doc/functional-tests.md similarity index 92% rename from test/README.md rename to doc/functional-tests.md index 97e9987ff..9785f1c4c 100644 --- a/test/README.md +++ b/doc/functional-tests.md @@ -1,166 +1,165 @@ -This directory contains integration tests that test bitcoind and its +The [/test/](/test/) directory contains integration tests that test bitcoind and its utilities in their entirety. It does not contain unit tests, which can be found in [/src/test](/src/test), [/src/wallet/test](/src/wallet/test), etc. -There are currently two sets of tests in this directory: +There are currently two sets of tests in the [/test/](/test/) directory: - [functional](/test/functional) which test the functionality of bitcoind and bitcoin-qt by interacting with them through the RPC and P2P interfaces. -- [util](test/util) which tests the bitcoin utilities, currently only +- [util](/test/util) which tests the bitcoin utilities, currently only bitcoin-tx. The util tests are run as part of `make check` target. The functional -tests are run by the travis continuous build process whenever a pull -request is opened. Both sets of tests can also be run locally. +tests are run by the Teamcity continuous build process whenever a diff is created or updated on Phabricator. Both sets of tests can also be run locally. -# Running tests locally +# Running functional tests locally Build for your system first. Be sure to enable wallet, utils and daemon when you configure. Tests will not run otherwise. ### Functional tests #### Dependencies The ZMQ functional test requires a python ZMQ library. To install it: - on Unix, run `sudo apt-get install python3-zmq` - on mac OS, run `pip3 install pyzmq` #### Running the tests Individual tests can be run by directly calling the test script, eg: ``` test/functional/example_test.py ``` or can be run through the test_runner harness, eg: ``` test/functional/test_runner.py example_test ``` You can run any combination (incl. duplicates) of tests by calling: ``` test/functional/test_runner.py ... ``` Run the regression test suite with: ``` test/functional/test_runner.py ``` Run all possible tests with ``` test/functional/test_runner.py --extended ``` By default, up to 4 tests will be run in parallel by test_runner. To specify how many jobs to run, append `--jobs=n` The individual tests and the test_runner harness have many command-line options. Run `test_runner.py -h` to see them all. #### Troubleshooting and debugging test failures ##### Resource contention The P2P and RPC ports used by the bitcoind nodes-under-test are chosen to make conflicts with other processes unlikely. However, if there is another bitcoind process running on the system (perhaps from a previous test which hasn't successfully killed all its bitcoind nodes), then there may be a port conflict which will cause the test to fail. It is recommended that you run the tests on a system where no other bitcoind processes are running. On linux, the test_framework will warn if there is another bitcoind process running when the tests are started. If there are zombie bitcoind processes after test failure, you can kill them by running the following commands. **Note that these commands will kill all bitcoind processes running on the system, so should not be used if any non-test bitcoind processes are being run.** ```bash killall bitcoind ``` or ```bash pkill -9 bitcoind ``` ##### Data directory cache A pre-mined blockchain with 200 blocks is generated the first time a functional test is run and is stored in test/cache. This speeds up test startup times since new blockchains don't need to be generated for each test. However, the cache may get into a bad state, in which case tests will fail. If this happens, remove the cache directory (and make sure bitcoind processes are stopped as above): ```bash rm -rf cache killall bitcoind ``` ##### Test logging The tests contain logging at different levels (debug, info, warning, etc). By default: - when run through the test_runner harness, *all* logs are written to `test_framework.log` and no logs are output to the console. - when run directly, *all* logs are written to `test_framework.log` and INFO level and above are output to the console. - when run on Travis, no logs are output to the console. However, if a test fails, the `test_framework.log` and bitcoind `debug.log`s will all be dumped to the console to help troubleshooting. To change the level of logs output to the console, use the `-l` command line argument. `test_framework.log` and bitcoind `debug.log`s can be combined into a single aggregate log by running the `combine_logs.py` script. The output can be plain text, colorized text or html. For example: ``` combine_logs.py -c | less -r ``` will pipe the colorized logs from the test into less. Use `--tracerpc` to trace out all the RPC calls and responses to the console. For some tests (eg any that use `submitblock` to submit a full block over RPC), this can result in a lot of screen output. By default, the test data directory will be deleted after a successful run. Use `--nocleanup` to leave the test data directory intact. The test data directory is never deleted after a failed test. ##### Attaching a debugger A python debugger can be attached to tests at any point. Just add the line: ```py import pdb; pdb.set_trace() ``` anywhere in the test. You will then be able to inspect variables, as well as call methods that interact with the bitcoind nodes-under-test. ### Util tests Util tests can be run locally by running `test/util/bitcoin-util-test.py`. Use the `-v` option for verbose output. # Writing functional tests You are encouraged to write functional tests for new or existing features. Further information about the functional test framework and individual tests is found in [test/functional](/test/functional).